A mobile terminal can be configured to perform various functions. Example of such various functions may include a data and voice communication function, a function of capturing still or moving images through a camera, a voice storage function, a function of reproducing music files through a speaker system, a function of displaying image of video files. Some mobile terminals may include an additional function for playing games, and some other mobile terminals may be implemented as a multimedia player. Moreover, new mobile terminals can receive broadcast or multicast signals, allowing the user to view video or TV programs.
Furthermore, the efforts for supporting and enhancing the function of the mobile terminal have been continued. The above efforts include addition and improvement of software or hardware as well as change and improvement of structural constituent elements constituting a mobile terminal.
Among them, the touch function of a mobile terminal allows even users who are unskilled in a button/key input using a touch screen to conveniently perform the operation of a terminal. In recent years, it has settled down as a key function of the terminal along with a user UI in addition to a simple input.
In general, mobile terminals perform wireless communication using a single baseband chipset (controller or processor) and a radio frequency (RF) unit. The aforementioned structure is beneficial to miniaturization and light weight of mobile terminals. However, in case where one RF unit is used in the foregoing single baseband structure, it has a drawback incapable of paging another channel while performing a phone call. In other words, in case of using a single RF chipset, only a standby or transmission/reception for one channel (single standby) can be made (single talk), but a concurrent standby or transmission/reception for another channel (double standby) cannot be made (double talk) during the same timeslot. As a result, the user has nothing to do but receive a limited level of communication quality or communication services in the existing signal baseband structure.
On the other hand, various identification modules, such as, user identity module (UIM), subscriber identity module (SIM), universal subscriber identity module (USIM), and the like, are used to authenticate the user's usage authority. The identification module is connected to a mobile terminal through a port. Among them, for the SIM, there are a single SIM and a dual SIM as a device for storing personal information to provide various services such as authentication, pricing, security, and other functions.
In a terminal employing the single SIM, there is used one SIM, which is connected to one processor. In a terminal employing the dual SIM, there are included a primary SIM (SIM A) and a secondary SIM (SIM B), and the primary SIM is connected to a first processor, and the secondary SIM is connected to a second processor.
However, SIM switching between processors cannot be implemented in mobile terminals having a conventional dual SIM structure. For example, in case where the first processor connected to the primary SIM supports both circuit switched (CS) and packet switched (PS) services but the second processor connected to the secondary SIM supports only CS services, then the second process supports only CS services even though the user wants to use packet services (for example, WAP, MMS, etc.) with a SIM connected to the second processor and thus the user cannot use his or her desired packet services. In this case, the user should manually change a configuration setting between the first and second SIMs and perform a power cycle to use packet services with the secondary SIM.